WorksheetsTopic 2 Review: Chemical Reactions
Total questions: 20
Worksheet time: 18mins
After reading about the kinds of mixtures and their characteristics, Jasmine wants to know how a heterogeneous mixture is different from a homogeneous mixture. What is the main difference between these two kinds of mixtures?
n a heterogeneous mixture, the components are not evenly spread throughout the mixture. In a homogeneous mixture, the components are evenly spread throughout the mixture.
In a homogeneous mixture, the components are not evenly spread throughout the mixture. In a heterogeneous mixture, the components are evenly spread throughout the mixture.
In a homogeneous mixture, the components are easy to see and are well mixed so the components show up in different parts of the mixture.
In a heterogeneous mixture, the components are difficult to see and are spread out uniformly throughout the mixture.
After reading that a solution is a homogeneous mixture, Jasmine wondered about her favorite morning drink, grape juice. Which statement about the solution that makes up grape juice is true?
Sugar is the solvent, and water is one of the solutes.
Water is the solvent, and sugar is one of the solutes.
Grapes are the solvent, and water is one of the solutes.
Sugar is one of the solvents, and grapes are one of the solutes.
Julia has been studying the best ways to separate different kinds of mixtures. After learning about how mixtures are classified, Julia saw a picture and immediately knew how it was classified. Look at the image. Then, circle the words that complete the sentence below to identify the kind of mixture shown and the best way to separate it.
This mixture is classified as a(n) (colloid / suspension / filter / evaporation), and the best way to separate it is by (evaporating / colloiding / suspending / filtering) it.
suspension, filtering
colloid, suspending
filter, evaporating
suspension, evaporating
Derrick decided to research what factors might affect the properties of the solubility of a solution. After completing his research, Derrick knew that several factors affected the properties of solubility. Explain the factors that affect the properties of the solubility of a solution.
Later that day, Will made toast and buttered it, but then he left the butter out on the warm stove. What kind of change would most likely take place with the butter?
Chemical
Physical
Liquid
Solid
Will wanted to explore these changes in more depth, so he compared the two kinds of ways matter changes and how they differ. He recorded his findings in his science notebook. What are the ways in which matter changes, and how do they differ?
Macy has been studying physical and chemical reactions in school. She read about chemical reactions and how energy is either required or released during chemical reactions. Which word describes the direction of heat flow illustrated in the picture?
Chemical
Endothermic
Exothermic
Physical
Choose the words that correctly complete the sentences.
After having studied chemical reactions in school, Jose knew that when oxygen and hydrogen gases combine in the correct amounts, the combination yields a new substance, water. The hydrogen and oxygen are (products / reactants / synthetics / polymers) while the water is the (product / reactant / synthetic / polymer).
products, reactant
reactants, synthetic
polymers, synthetic
reactants, product
Alex saw a rusty old car in an abandoned lot. Because he had recently read about chemical reactions, he began to wonder how the rust formed. What happened to cause the rust on the steel car?
A physical change took place in the steel of the car to form rust.
Oxygen in the air reacted with the paint on the car and formed rust.
Oxygen in the air chemically combined with the iron in the steel to form rust.
A decomposition chemical reaction took place when the iron in the steel mixed with oxygen to form rust.
After learning about the law of conservation of mass, Remy began to wonder about how to best test this law. She wanted to show that the amounts of matter did not change but produced an equal amount of a different kind of matter. What is the best way to study this law?
in a homogeneous mixture
in a heterogeneous mixture
in an open system
in a closed system
Choose the words that correctly complete the sentence below.
After learning about the law of conservation of mass, Sammy became interested in balancing equations. He knew that the symbol for aluminum was Al and silver tarnish was Ag2S. He also knew that mixing the two chemicals yielded pure silver, or Ag, in an aluminum sulfide solution. Here is the equation showing this reaction:
3 Ag2S + 2 Al → 6 Ag + Al2S3
This equation is (synthesis / unbalanced / replacement / balanced), and it represents a(n) (unbalanced / balanced / synthesized / replaced) chemical reaction.
synthesis; balanced
balanced; replacement
unbalanced; synthesized
balanced; balanced
Calvin was using super glue one afternoon after learning about synthetic materials. He understood that chemists create different kinds of new products based on their knowledge of the properties of substances and how they react with each other. What kind of product is super glue?
accidental
developed
exothermic
planned
Luisa likes to drink water from a plastic bottle. She knows the bottles were formed from synthetic polymers that were created in a chemical reaction. She also knows that synthetic materials can cause problems. Which statement explains the kind of problem that can develop from using synthetic materials such as plastic?
Plastics have changed the way people use materials.
Plastics have made the lives of people easier.
Plastics have contributed to more pollution.
Plastics have made more work for people.
14. Robert read more about food preservatives after studying synthetic materials in school. He wanted to know more about the way food preservatives interact and their effects. Read each of the phrases that describe benefits and drawbacks of using synthetic food preservatives. Identify which phrases are benefits and which phrases are drawbacks.
cheaper to produce in large amounts • affects health • keeps food fresh longer • unknown effects in the future • can make food safer • can substitute for unavailable or scarce foods
In a heterogeneous mixture, the substances....
can be physically separated.
are chemically combined.
can only be separated through chemical processes.
break down into new substances.
Which of the following statements is true?
A solution is a pure substance
A solution is a mixture
The solvent is dissolved in the solute.
A solution has the same properties as a colloid.
Which of following is an example of a chemical change?
breaking a rock into smaller pieces.
burning a candle.
stirring butter and sugar together
adding food coloring to water
In general, what happens to the rate of reaction when you decrease the temperature of a chemical reaction?
decreases
increases
it's unaffected
it increases, and then decreases
Burning a log is an example of...
an endothermic reaction
a solution
a catalyst
an exothermic reaction
Trail mix is an example of what kind of...
mixture
solution
